Spabk-plttg



J. A. LAING.

SPARK PLUG.

APPLICATION FILED ocr. 21. 1918.

1,3 1 6, 904. Patented Sept. 23, 1919.

awucwtoz JmeJ/I. Laz'xy my 3 M 4.1%;

C] Home UNITED STATES PATENT ()FFICE.

JAMES A. LAING; OF S POKANE, "WASHINGTON, ASSIGNOR 0F ONE-THIRD TO FRED B.

PEKGELLY AND CHE-THIRD TO CLYDE C.

INGTONI BATLIFF, BOTH 01E SPOKANE, 'WASH- SPARK-PLUG.

misses.

To all whom it may concern:

, Be it known that 1, JAMES A. LAING, a citizen of United States, residing at Spokane, in the county of Spokane and State of Washington, have invented certain new' and useful Improvements in Spark-Plugs,

'of which the following is a specification.

The present invention relates to an improved spark plug which is'designed especially for overcoming existing diiliculties 7 avoid poorcircuit making with'its consequent troubles.

The invention consists in certain novel combinations and arrangements of parts involving the use of a metal cup or cap on one of the clamping nuts for the terminal wires, and in the means for attaching said cup to the clamping nut, as will be hereinafter pointed out. in the specification and claims.

In the accompanying drawings one complete example and a slight modification thereof is illustrated, showing the physical embodiment of the invention constructed and arranged according to the best mode so far devised for the practical application of the principles of the invention. I

' Figure 1 is a' view, showing the end of a spark plug of usual type with the clamping nut and terminal cup or cap therein, em

threaded end for the wire terminal clamping nut i. Preferably the clamping nut is of the butterfly type having the wings 5, 5,

Specification of Letters Patent. Pat nted Sept. 23, 1919.

Application filed October 21, 1918. Serial No. $59,118.

so that the nut may be turned on the threaded stem, without'recourse to tools, which often cause breakage of the porcelain 0st.

At the base of the nut, which is preierably cylindrical, is provided a brass cup 6, also cylindrical in shape and provided with the annular flange 7 to fit around the end of the nut, there being an opening 8 in the center of the cup for the conductor stem. The cup is formed with an annular rib 9, which is ,of V-shape in cross section thus providing it with a tapered interior which is adapted to embrace and fit over the loop formed in the terminal wire when said loop is placed over or hooked around the stem 3. After the terminal is placed about the stem, the nut is turned home and the-tapered cup, as it is turned in close contact with the lodp, forces the loop up against the bottom Bof the cup to make the proper contact. 'lthe friction between thewireloop and the interior of the cup insures a clean surface of these parts, and of course the clean surface insures a good terminal contact -for the wires. The terminal loop is clamped {between the cup 6 and the cap 2, on the end of the porcelain post, and thus a positive contact and connection are provided for the terminal wires.

To retain the cup (Son the end of the clamp nut, a series of grooves 10 are provided in the exterior surface of the hilt, which grooves are of bayonet formation, and adapted to receive the boss or bosses 11, projectmg from the interior surface of the wall or flange 7 These bosses are stamped or struck up from the metal of theflange and fit neatly in the grooves so that they may move in the grooves when the nut is turned, toward either end ofthe-groove, but will retain the cup on the end of the nut. The cup may readily be attached or detached through the instrumentaiit'y of the boss- E emme and said cup having a ortion thereon to said bosses to retain the cup on the nut, a frictionally engage the wlre terminal for the projecting rib on the cup of circular forma- I electrical connection to the plug. tion and \l-shape in cross section and adapt- 10 2. The combination in a spark plug with ed to clamp the Wire terminal on said cap, 5 the clamp nutthereon, of a metallic cup as described.

having lnteriorly' projecting bosses and In testimony whereof I afiix my signature. grooves in the exterior face of the nut for J AMES A. LAING. 

